How pembrolizumab works

Pembrolizumab is a monoclonal antibody that binds to the PD-1 receptor and blocks its interaction with PD-L1 and PD-L2, releasing PD-1 pathway-mediated suppression of immune responses, including anti-tumor immune responses. In syngeneic mouse tumor models, blocking PD-1 activity resulted in decreased tumor growth. The PD-1 ligands PD-L1 and PD-L2 bind to the PD-1 receptor on T cells and inhibit T cell proliferation and cytokine production. Upregulation of PD-1 ligand occurs in some tumors, and signaling through this pathway may contribute to suppression of active T cell immune surveillance of tumors.